Design Methodology for Design and Selection of Vehicle Head Impact Countermeasures

This paper presents two methods for the design of energy absorber countermeasures meeting FMVSS 201u head impact test requirements. The two methods are a preliminary design method for the quick sizing of countermeasures and an LS_DYNA simulation method. The minimum stroke and minimum countermeasure size is presented as a series of “look up” tables and charts for 80% efficient countermeasures. A second detail design method employing LS_DYNA impact simulation is then presented which employs simplified material cards and property cards determined by the first methodology. The design procedure is illustrated by an actual production countermeasure selection procedure. The predicted performance is compared to test performance. LS_DYNA models of the absorber with equivalent shell element material and property cards are described which would allow CAE groups to conduct vehicle application studies.